0Chapter 1 motion
The rate of change of a position concerning specific the frame of reference. It's opposite of rest. Motion is everywhere but there's nothing about an absolute motion or an absolute rest. All motion in the universe is relative to each other it's mean no absolute value of motion. This chapter focuses on relative motion only.
To the analysis of motion is requires a frame of reference, which may be fixed or movable best example is earth surface is a fixed frame of reference with respect terrestrial motion. Mathematically frame of text can be described as geometric coordinate systems example earth can represent on spherical coordinate systems with radius nearly 6500 km and similarly sun with 109 times larger space.
Vector is quantity having a certain direction to apply to is called the line of action. It Can be represented as bow method or blod latter's its has special properties such as a sum of the vector can be zero. Vectors must follow the triangular additional or parallelogram law. Multiplication of vector is different from ordinary scalar properties. Note that electric current and work done is scalar quantity due to its doesn't follow vectors new laws. Vector was advanced topic eighteen-century science still use today to the analysis of motion. Displacement, Velocity, acceleration and force are considered as a vector quantity.
the proper definition of particles is a body having mass applying on the centre of gravity is the only point whereas all effects can be balanced but its dimensions are not considered in the analysis. Example consider your mobile is rest in your hand while you are moving with your surroundings arise questions are mobile is moving with respect surroundings or moving with respect to you. To answer these types questions are difficult without fixing a frame of reference because without a frame of reference we can't tell the difference between motion or rest.
Some motion can be treated as rest but its motion example at atomic level scale electrons are travelling near the speed of light and orbit around the nucleus of an atom that analysis is considered as microscopic levels whereas human senses activity considers as macroscopic levels where activity in atomic scales are highly negligible. The same problem also happens in Cosmo levels for example Consider earth as a particle moving in a circular orbit around the sun in a year. Sun is also moving an orbit to the star named sage A* in 250 million years which is centre of the galaxy. Our galaxy is moving towards a bigger galaxy as per telescopic observation in the night sky as per comparison of scale here activity on earth such as movements of people's and animals can be considered as neglected. Sence of motion requires a frame of reference.
As conclusion "nothing is absolute motion or absolute rest " all motion is relative.
It's all about motion.
Next topic is displacement and distance.
